Naurr I believe it's because Noi experienced the uh separation/splitting thingie that Owen's species goes thru (not really sure how to word it)
I skimmed through that particular explanation but I think Owen split through so many timelines for Nux that there are as many possibilities of Noi existing as there are Owen's. So he had to get all the Noi's from different timelines since all the Owens were with him (two frozen and two sulking). Sooo I think that's the reason.
It's because Owen is part of a certain alien race that gets split into 5 people but has intertwined consciousness and inherited that. At least that's from my understanding of the plot since s1
I also think it was because of the Asangard species (whatever u call it) cuz it was said that the Nois started appearing all over at different times (explaining why the Nois are not the same age) and that it was a normal process for their species. They were even prepared for it as far as I know
Wait wait wait..why there has a lot of nois? Did I miss a chapter..did our ML go and make other Owen pregnant?..uhhh can anyone explained to me